2001 Yamaha YZ125(N)/LC Owner's Service Manual (P/N 5MV-28199-30)

This official 558-page Yamaha OEM publication (P/N 5MV-28199-30, first edition June 2000) is the factory-authorized reference for the 2001 YZ125(N)/LC series. It specifically documents liquid-cooled 2-stroke engine performance, chassis settings, and 6-speed transmission specifications for the 5MV-series build.

• Contains over 50 exploded-view diagrams
• Features comprehensive torque tables
• Includes detailed maintenance interval schedules for racing preparation
• Covers critical break-in procedures for internal components and specialized tuning adjustments

Documentation Overview

The service manual provides an in-depth look at the operational procedures, inspection points, and basic maintenance tasks required to keep this machine race-ready. Organized into seven distinct chapters, the text breaks down the technical layout of the engine, chassis, and electrical systems. It offers clear reference material for engine removal, transmission assembly, and front fork adjustments. The publication covers all global variants, ensuring accurate assembly specs regardless of the domestic or international configuration you are working on. Working on high-performance dirt bikes carries inherent risks, so referencing these factory-approved torque sequences and structural limits is crucial to maintain structural integrity and prevent equipment failure or personal injury during a ride.

Specification and Technical Reference

Mechanics will find detailed specifications for every major mechanical component. This includes critical parameters like piston-to-cylinder clearance, gear ratios, and cooling system capacities. The engine assembly data calls out specific torque values, noting 28 Nm for the cylinder head nuts and 80 Nm for the clutch boss, allowing for precise bench work.

The diagnostic charts deliver hard numbers for electrical troubleshooting, such as the CDI magneto pick-up coil resistance specified at 248–372 ohms. You also get exact fluid requirements, with the coolant system capacity listed at 1.00 liters to assist with radiator top-offs and flushes. Reed valve inspection data is mapped out in the engine tables to help verify intake tolerances.